Autism, oxytocin and interoception.

Autism is a pervasive developmental disorder characterized by profound social and verbal communication deficits, stereotypical motor behaviors, restricted interests, and cognitive abnormalities. Autism affects approximately 1% of children in developing countries. Given this prevalence, identifying risk factors and therapeutic interventions are pressing objectives—objectives that rest on neurobiologically grounded and psychologically informed theories about the underlying pathophysiology. In this article, we review the evidence that autism could result from a dysfunctional oxytocin system early in life. As a mediator of successful procreation, not only in the reproductive system, but also in the brain, oxytocin plays a crucial role in sculpting socio-sexual behavior. Formulated within a (Bayesian) predictive coding framework, we propose that oxytocin encodes the saliency or precision of interoceptive signals and enables the neuronal plasticity necessary for acquiring a generative model of the emotional and social 'self.' An aberrant oxytocin system in infancy could therefore help explain the marked deficits in language and social communication—as well as the sensory, autonomic, motor, behavioral, and cognitive abnormalities—seen in autism

Alexithymia, but not Autism Spectrum Disorder, may be Related to the Production of Emotional Facial Expressions

Background A prominent diagnostic criterion of autism spectrum disorder (ASD) relates to the abnormal or diminished use of facial expressions. Yet little is known about the mechanisms that contribute to this feature of ASD. Methods We showed children with and without ASD emotionally charged video clips in order to parse out individual differences in spontaneous production of facial expressions using automated facial expression analysis software. Results Using hierarchical multiple regression, we sought to determine whether alexithymia (characterized by difficulties interpreting one’s own feeling states) contributes to diminished facial expression production. Across groups, alexithymic traits—but not ASD traits, IQ, or sex—were associated with quantity of facial expression production. Conclusions These results accord with a growing body of research suggesting that many emotion processing abnormalities observed in ASD may be explained by co-occurring alexithymia. Developmental and clinical considerations are discussed, and it is argued that alexithymia is an important but too often ignored trait associated with ASD that may have implications for subtyping individuals on the autism spectrum

Nicotinic receptors

Regulation of normal or abnormal behaviour is critically controlled by the central serotonergic systems. Recent evidence has suggested that serotonin (5-HT) neurotransmission dysfunction contributes to a variety of pathological conditions, including depression, anxiety, schizophrenia and Parkinson’s disorders. There is also a great amount of evidence indicating that 5-HT signalling may affect the reinforcing properties of drugs of abuse by the interaction and modulation of dopamine (DA) function. This chapter is focused on one of the more addictive drugs, nicotine. It is widely recognised that the effects of nicotine are strongly associated with the stimulatory action it exhibits on mesolimbic DAergic function. We outline the role of 5-HT and its plethora of receptors, focusing on 5-HT2 subtypes with relation to their involvement in the neurobiology of nicotine addiction. We also explore the novel pharmacological approaches using 5-HT agents for the treatment of nicotine dependence. Compelling evidence shows that 5-HT2C receptor agonists may be possible therapeutic targets for smoking cessation, although further investigation is required.peer-reviewe

Functional neuroanatomy of interoceptive processing in children and adolescents: a pilot study

In adults, interoception – the sense of the physiological condition of the body - appears to influence emotion processing, cognition, behavior and various somatic and mental health disorders. Adults demonstrate frontal-insula-parietal-anterior cingulate cortex activation during the heartbeat detection task, a common interoceptive measure. Little, however, is known about the functional neuroanatomy underlying interoception in children. The current pilot study examined interoceptive processing in children and adolescents with fMRI while using the heartbeat detection task. Our main findings demonstrate that children as young as the age of six activate the left insula, cuneus, inferior parietal lobule and prefrontal regions. These findings are similar to those in adults when comparing heartbeat and tone detection conditions. Age was associated with increased activation within the dACC, orbital frontal cortex and the mid-inferior frontal gyri. Thus, our pilot study may provide important information about the neurodevelopment of interoceptive processing abilities in children and a task for future interoception neuroimaging studies in children

The feeling of me feeling for you: Interoception, alexithymia and empathy in autism.

Following recent evidence for a link between interoception, emotion and empathy, we investigated relationships between these factors in Autism Spectrum Disorder (ASD). 26 adults with ASD and 26 healthy participants completed tasks measuring interoception, alexithymia and empathy. ASD participants with alexithymia demonstrated lower cognitive and affective empathy than ASD participants without alexithymia. ASD participants showed reduced interoceptive sensitivity (IS), and also reduced interoceptive awareness (IA). IA was correlated with empathy and alexithymia, but IS was related to neither. Alexithymia fulfilled a mediating role between IA and empathy. Our findings are suggestive of an alexithymic subgroup in ASD, with distinct interoceptive processing abilities, and have implications for diagnosis and interventions

Cardio-visual full body illusion alters bodily self-consciousness and tactile processing in somatosensory cortex.

Prominent theories highlight the importance of bodily perception for self-consciousness, but it is currently not known whether this is based on interoceptive or exteroceptive signals or on integrated signals from these anatomically distinct systems, nor where in the brain such integration might occur. To investigate this, we measured brain activity during the recently described ‘cardio-visual full body illusion’ which combines interoceptive and exteroceptive signals, by providing participants with visual exteroceptive information about their heartbeat in the form of a periodically illuminated silhouette outlining a video image of the participant’s body and flashing in synchrony with their heartbeat. We found, as also reported previously, that synchronous cardio-visual signals increased self-identification with the virtual body. Here we further investigated whether experimental changes in self-consciousness during this illusion are accompanied by activity changes in somatosensory cortex by recording somatosensory evoked potentials (SEPs). We show that a late somatosensory evoked potential component (P45) reflects the illusory self-identification with a virtual body. These data demonstrate that interoceptive and exteroceptive signals can be combined to modulate activity in parietal somatosensory cortex

Direct and indirect effects of age on interoceptive accuracy and awareness across the adult lifespan

Various aspects of physical and mental health have been linked to an individual’s ability to perceive the physical condition of their body (‘interoception’). In addition, numerous studies have demonstrated a role for interoception in higher-order cognitive abilities such as decision-making and emotion processing. The importance of interoception for health and typical cognitive functioning has prompted interest in how interoception varies over the lifespan. However, few studies have investigated interoception into older adulthood, and no studies account for the set of physiological changes that may influence task performance. The present study examined interoception from young to very late adulthood (until 90 years of age) utilising a self-report measure of interoception (Study One) and an objective measure of cardiac interoception (Study Two). Across both studies interoception decreased with age, and changes in interoceptive accuracy were observed which were not explained by accompanying physiological changes. In addition to a direct effect of age on interoception, an indirect effect of ageing on cardiac interoceptive accuracy mediated by body mass index (BMI) was found, such that ageing was associated with increased BMI which was, in turn, associated with reduced interoceptive accuracy. Such findings support and extend previous research demonstrating interoceptive decline with advancing age, and highlight the importance of assessing whether decreasing interoceptive ability is responsible for some aspects of agerelated ill-health and cognitive impairment